This invention relates to an electric compressor.
Reciprocating electric compressors are generally provided with a cylinder which has a cylinder chamber and inlet and outlet ports opening into the cylinder chamber. The inlet and outlet ports are provided with a valve each. The valves open and close the inlet and outlet ports as the piston in the cylinder chamber reciprocates, thereby controlling the suction of gas into the cylinder chamber and the discharge of compressed gas from the cylinder chamber.
Since the valves are generally formed of valve plates, however, it is difficult for the valves exactly to follow the action of the piston, and a slight time lag is caused. This time lag will induce overcompression or overexpansion of the gas to be compressed and lower the volumetric efficiency. Moreover, the valves may break due to metal fatigue after prolonged use. The failure of the valves is the most frequent cause of troubles of compressors. Also, the valves may produce noise, and the use of the valves will increase the number of parts used and hence maufacturing cost.
Scroll- or screw-type compressors as a kind of rotary electric compressors use no valves, and are free from the aforementioned problems. The compressors of this type, however, are complicated in construction, and are low in manufacturing efficiency.
Also provided are reciprocating compressors without a suction valve, reciprocating compressors with neither a suction valve nor a delivery valve, and compressors without a delivery valve. These compressors, however, have the basic structure of a reciprocating or rotary compressor. Accordingly, the compressing conditions of the compressors may be adversely affected by the reduction or elimination of the valves. For example, a groove or a hole formed in the cylinder chamber to be used in place of the delivery valve will function like the top clearance of the cylinder chamber, thereby lowering the compression efficiency of the compressors.
Further, there is provided a compressor whose construction is quite different from those of the aforementioned conventional compressors. This compressor comprises a rotating disk in a casing and a non-rotating disk pushed toward the rotating disk by a spring. These two disks have corrugated contact surfaces to be in contact with each other. Gas to be compressed is sucked in between the contact surfaces for compression. In this compressor, the contact surfaces need be brought perfectly into contact with each other for secure compression of the gas. It is therefore very troublesome to work the contact surfaces. Moreover, this compressor includes many contact regions, and the contact surfaces are susceptible to abrasion. The compressor of this construction further has a plurality of inlet and outlet ports which penetrate the rotating and non-rotating disks and open into depressions in the contact surfaces. A check valve is provided in each of the ports. Thus, this compressor has a number of inlet and outlet ports, and requires additional working. Moreover, the use of the check valves in the ports adds to the number of parts. Furthermore, the amounts of compressed gas passing through the individual ports are liable to fluctuations, so that it is very hard to ensure efficient compression.